1. Field of the Invention
This invention relates to a picture encoding apparatus, and more particularly, is suitably applicable to a picture encoding apparatus for transmitting such pictures that a large quantity of information is generated in high efficiency encoding.
2. Description of the Related Art
In a prior art picture encoding apparatus of this kind, there has been such an arrangement that a motion vector of a picture to be transmitted is previously obtained to encode the picture signal, and then the picture to be transmitted is transformed according to the motion vector, thereby enhancing a transmission efficiency and a compression efficiency.
Here, it is conceived that the picture to be transmitted has generally a high correlativity between picture signals of two consecutive frames unless a scene change, therefore the quantity of information is compressed by obtaining a difference between picture data of the consecutive frames which is sequentially encoded thereafter.
With reference particularly to a portion of a moving picture, a quantity of information of the difference increases all the more if merely obtaining the interframe difference, therefore it is general that blocks of a previous frame are moved vertically and horizontally by a motion vector of the previous frame to be shifted in respective directions so that a block in which a quantity of information generated between each picture element of the previous frame and that of the present frame is minimized is obtained, thereby compressing the quantity of information.
Here, the picture encoding apparatus is arranged such that the previous frame is shifted in the directions x and y according to the motion vector of a previous block, so as to decide that a vector to the shifted block upon which the sum of difference absolute values of picture elements of the present block and the shifted block in all directions is minimized becomes the motion vector of the present block.
Meanwhile, in a case where such picture encoding apparatus is constructed, a simulation on a computer is widely utilized for appreciating a performance and effect of the system beforehand.
However, in many cases, there is required a so long time for the simulation to pictures, and particularly, in the case of pictures of a high precision TV broadcasting (or a so-called HDTV (High Definition TV)) in which a picture element of the picture to be processed is many in number, several hours are required for completing a picture processing by one second even using a supercomputer, thereby it is inconvenience to examine into the procedure.
Therefore, a method in which a hardware for exclusive use on simulation is designed, and picture information changing at real time is ensured thereon is employed in most cases. However, it is difficult to carry out an analysis of information extracted from among various items of information on the picture as required.
Accordingly, if such a circuit as is capable of confirming visually local information in picture encoding by a switch operation as in the case where the picture is observed on a monitor is realized, then a convenience will be ensured for examining into an improvement of quality of pictures and a construction of the system. Moreover, operation of each circuit can be accurately caught in manufacturing a hardware by way of trial, therefore a debugging efficiency is improved.